1. Field of the Invention
The present invention relates to a wide slit nozzle and a method by such wide slit nozzle, that are used for coating a coated-type vibration damping material on a vehicle or the like, while overlapping part of coated material sheets without a gap, so that the coated material is capable of improving vibration damping ability, and that can be used for general purpose coating.
2. Description of the Related Art
A vibration damping material is spread out on a vehicle floor for the purpose of vibration damping and noise control. An asphalt sheet has been used for such vibration damping material so far, but some problems still remain. That is, powders resting on a surface cause irregularity on the surface after painting. Moreover, workers need to work hard since 5 to 15 kg of the asphalt sheet must be constructed per one automobile. Furthermore, the asphalt sheets require a large storage space. To improve those demerits, a new art has been developed which coats a material having vibration damping effects on the automobile floor instead of spreading the asphalt sheet. One conventional example is disclosed in Japanese Laid Open Patent Publication No. 2000-237679.
In this prior invention, acrylic emulsion type water soluble coating material is used as the vibration damping material of the vehicle floor. The surface of the vehicle body's floor is coated with the vibration damping material using a nozzle having a special opening, so that a coating film or layer that has a grid or grating pattern is formed on the surface. Thereby, more reliable noise control effect can be obtained.
Referring to FIGS. 5(a) to 5(c), problems of such technique are to be explained. FIG. 5(a) is a front elevation view of a conventional nozzle seen from a discharge face side. FIG. 5(b) is a perspective view showing a case of coating vibration damping materials with their edges overlapped on a vehicle floor using the conventional nozzle. FIG. 5(c) is also a perspective view showing a case of coating the vibration damping materials with a certain space there between. Moreover, in FIGS. 5(a) to 5(c), a height or a thickness of a slit is illustrated much bigger to a length thereof. An actual height of the slit is very small. A thickness of the vibration damping material discharged from the slit is much larger than the height of the slit, since it is applied with a pressure.
As shown in FIG. (a), in the technique described in the publication, the slit or a discharge opening 12 of the nozzle 11 has an even height γ from one edge to another edge. So, when vibration damping material lines P3 and P4 are coated side by side, if the previous line P3 and the present line P4 are coated with their edges overlapped, such overlapped part rises much higher than the other parts as shown in FIG. 5(a). Accordingly, the higher part interferes with parts or components mounted on the vehicle floor and pipe arrangements lined on the floor.
To prevent such interference, a space 15 is set between the previously coated line P3 and the presently coated line P4 in a practical use, as shown in FIG. 5(c). Though, it has become clear that this space 15 causes a bigger vibration in a certain frequency, so that vibration damping ability degrades.